9 factorial

solutions/factorial.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+A module contains afunction  to compute the factorial of a number
+
+Module contents:
+    -factorial: a function  to compute the factorial of a number
+
+created on 9 Jan 2025
+Author: Azza Ibrahim
+
+"""
+
+
+def factorial(number: int) -> int:
+    """
+    A function computes a factorial of a number
+
+    parameters :
+    Number (int) : the number to compute its factorial
+
+    Return:
+    int : THE fsctorial of the inpiut number
+
+    Raises:
+    ValueError: Factotial is only defined for positive numbers
+
+    """
+    if number == 0 or number == 1:
+        return 1
+
+    if number < 0:
+        raise ValueError("Factotial is only defined for positive numbers")
+
+    res = 1
+    for f in range(2, number + 1):
+        res *= f
+
+    return res

solutions/tests/test_factorial.py

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+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+A module contain test cases for factorial function
+
+Test categories:
+        normal cases
+        bounry cases
+        defensice assertaion
+
+
+created on 12 Jan 2025
+Author: Azza Ibrahim
+"""
+
+import unittest
+from ..factorial import factorial
+
+
+class TestFactorial(unittest.TestCase):
+    """
+    Class contiain unit tests for factorial function
+    """
+
+    def test_factorial_positive(self):
+        """test factorial for a positive input number"""
+        self.assertEqual(factorial(5), 120)
+
+    def test_factorial_zero(self):
+        """TEst factorial functipn fo input of zero"""
+        self.assertEqual(factorial(0), 1)
+
+    def test_factorial_one(self):
+        """test factorial for input one"""
+        self.assertEqual(factorial(1), 1)
+
+    def test_factorial_large(self):
+        """test factorail for large input number"""
+        self.assertEqual(factorial(11), 39916800)
+
+    def test_negative(self):
+        """test negative input will raise error"""
+        with self.assertRaises(ValueError):
+            factorial(-3)
+
+    def test_non_intger(self):
+        """test case for non intger input"""
+        with self.assertRaises(TypeError):
+            factorial(5.5)
+
+
+if __name__ == "__main__":
+    unittest.main()